1. Field of the Invention
This invention relates to a sensor assembly and more particularly, to a sensor and display assembly adapted for use in combination with a die and effective to selectively determine whether the upper and lower die halves are in a parallel relationship and to indicate a minimum distance between the upper and lower die halves.
2. Discussion
Dies are normally used to form a generally rectangular metal blank into a certain and predetermined shape. A typical die includes a substantially stationary lower blank reception portion having a contoured top surface, formed into the certain and predetermined blank-forming shape. The die further includes a top portion which is movable from a first position remote from the lower portion, to a second lower position, where the top die has engaged the blank and forced it fully against the contours of the lower die.
The top die portion includes a generally flat top surface having a protruding or contoured portion which is adapted to mate with the contoured top surface of the lower die. In the second lower die contacting position, the top protruding portion deforms the blank against the contoured top surface of the lower die portion, thereby forming the blank into a shape substantially similar to the shape of the lower die contour.
In order to ensure that the blank is formed into the predetermined and desired shape, the top surface of the upper die must remain substantially parallel to the top surface of the lower die, thereby ensuring that all portions of the blank are forced into the desired engagement with the lower die contours. Moreover, as is further known to those of ordinary skill in the art, in order to prevent excessive blank deformation, the generally flat top die surface must also remain a predetermined and certain distance above the top surface of the lower die during mating. This distance is referred to as "the minimum shut height".
In the past, many hours have been spent manually aligning the die halves, by a trial and error procedure, in order to properly ensure that the top and lower halves are in a parallel relation and that a certain and desired minimum shut height is achieved. Though inefficient, such manual alignment is initially effective in aligning the top and bottom halves, provided that those individuals performing such manual alignment are experienced in such die alignment.
Once properly aligned, continued operation may cause the relative positions of the die halves and the shut height to become misaligned and to change. The degree of these misalignments increases over time. Typically, the existence of such misalignments is not visually noticeable until severely deformed blanks are produced. However, misalignments of a lesser degree may still produce unacceptable blanks which are outside of allowable tolerances. No method currently exists for automatically determining such misalignment absent an exhaustive and continual manual visual inspection of the produced blanks.
There is, therefore, a need to automatically and continually sense or monitor the existence of parallelism between the first movable die portion and the second stationary lower die portion, and to automatically and continually sense or monitor the minimum die shut height.